The present invention relates to a locking device for locking a movable member such as a cover to a body in a closed state, and more particularly, relates to a locking device for unlocking a movable member through pressing an operating button.
A locking device shown in FIGS. 8(a) and 8(b) is disclosed in Patent Reference 1. The locking device includes an operating button 52 and a lock member 53 disposed in a case 51. When the operating button 52 is pressed against an urging force of a spring member 54, the lock member 53 switches from a locked position for restricting a cover 61 to rotate relative to a storage body 60 (refers to as a locked state) to an unlocked position for allowing the cover 61 to rotate in an opening direction (refers to an unlocked state).
The case 51 is formed of a recess portion including an open portion of the storage body 60, and slide slots 51a and 51b are formed in opposing walls of the recess portion. The lock member 53 has a tab 53a at a tip thereof for coming in and out of the slide slot 51a; a rear shaft 53b inserted into the slide slot 51b; and a coupling hole 53c disposed in a mid section thereof. The lock member 53 is moved toward the locked position by the urging force of the spring member 54 axially fitted in the shaft 53b, while the tab 53a and the shaft 53b are fitted in slide slots 51a and 51b, respectively.
The operating button 52 is formed of an operating section 52a; a sliding section 52b inserted into the coupling hole 53c; and an anti-slip tab 52c disposed at the rear end of the sliding section 52b. The operating button 52 is assembled in the lock member 53 such that a slanted end face of the sliding section 52b abuts against a slanted end face of the coupling slot 53c. In an assembled state, the lock member 53 is urged toward the locked position as shown in FIG. 8(a).
When the cover 61 is closed, the cover 61 rotates and abuts against the tab 53a just before the closed state, so that the lock member 53 retreats to the unlocked position due to a reactive force against the urging force of the spring member 54. When the lock member 53 faces the recess 62, the lock member 53 engages the recess 62. When the cover 61 is opened, the operating button 62 is pressed with a finger or the like, so that the lock member 53 retreats to the unlocked position against the urging force of the spring member 54, thereby releasing the lock member 53 from the recess 62 as shown in FIG. 8(b).
Patent Reference 1: Japanese Patent Publication (Kokai) No. 11-159215.
The locking device described above has a simple structure and the following problems. First, the lock member 53 is always urged toward the locked position to project from the case 51. During the opening operation of the cover, when a pressure is removed from the operating button 52 after pressing the same, the cover instantaneously returns to the original locked position with the urging force. Accordingly, depending on a rotational speed of the cover 61, the lock member may engage the recess 62 again, thereby restricting the rotation of the cover. In the locking device disclosed in Patent Reference 1, the cover 61 is a rotating type, and a sliding type may have the same problem.
Second, the operating button 52 is assembled in the lock member 53 such that the sliding section 52b is inserted into the coupling hole 53c and the slanted end faces abut against each other. Accordingly, dust or the like may accumulate, for example, between the slanted end faces. In this case, when the pressure is removed, the lock member 53 may not return to the original projected position or the locked position smoothly. Further, the lock member 53 may vibrate or move up and down, thereby causing malfunction.
Third, an elastic member may be disposed at a portion where the body abuts against the cover for absorbing an impact or preventing rattle. In such a case, when the cover is closed for a prolonged period of time, the elastic member may deform and deteriorate, thereby sticking the body and the cover together. Accordingly, even if the operating button is pressed to switch the lock member to the unlocked position, it is difficult to switch the lock member to the opened state.
In view of the problems described above, an object of the present invention is to provide a locking device with a simple structure capable of easily switching a movable member such as a cover to an open state, thereby improving quality and ease of use.
Further objects and advantages of the invention will be apparent from the following description of the invention.